After another week of licking/scratching we went back to the vets again last night and finally they agree we need to do more than anti-biotics, steroid injections. Maisy had bloods taken last night and is booked in for a biopsy on her neck of Friday. She will be sedated and the vet will also have a look inside to see if anything is there. This vicious circle of healing then taking the collar off for more scratching/licking has been going on for over 4 months, maybe finally I will get an answer as to the cause.